The majority of instrumentations of blood vessels are carried out transcutaneously. In most instances, this requires the use of a transcutaneous introducer catheter, hereinafter referred to as the introducer. The introducer remains in the vessel of the patient during the course of the operation to provide the operating physician with means to insert and remove various medical apparatus efficiently. A problem arises in that once the introducer catheter is inserted into the vessel, the blood in the vessel is able to flow freely out of the invaded vessel through the introducer. In the past, in order to prevent the reflux of blood from the introducer, the physician placed his finger over the outlet of the introducer.
In response to the aforementioned problem, several diaphragm valves have been developed to prevent the reflux of fluid from the introducer upon insertion into the vessel. These diaphragm valves operate in conjunction with the introducer. They generally contain a small hole so various medical devices can be introduced by the physician through the introducer and into the vessel. The diaphragm valve surrounds the inserted apparatus for example, a catheter, thereby preventing the reflux of fluid out of the introducer. To prevent blood reflux, it is necessary for the diaphragm valve to fit snugly around the medical apparatus. However, as a result of the high friction level required between the diaphragm valve and the inserted device to prevent the reflux of blood (i.e., controlled bleeding), the tactile sensation and ability to manipulate and maneuver the device by the physician are reduced. While the diaphragm valve reduces the reflux of fluid, the problems associated with the high friction level are undesirable.
A number of patents disclose fluid flow control devices. U.S. Pat. No. 4,705,501 discloses a bidirectional anti-reflux vascular access system for the infusion of liquids into a body or for the aspiration removal of liquid samples from the body. A catheter formed from a pair of concentric inner and outer tubes is used as a fluid control. The inner tube is partially collapsed and closed at its distal end. The outer tube closely engages the inner tube and defines a catheter lumen therewith when the inner tube is collapsed by evacuation. To prevent movement of the tubes relative to each other, the inner and outer tubes are joined longitudinally over a small portion of the circumference of the inner tube. Also, U.S. Pat. No. 4,846,806 discloses an implantable intravascular access system which utilizes the catheter of the '501 patent.
U.S. Pat. No. 4,932,633 suggests a hemostasis valve gasket for use in the introducer. This gasket is formed from a resilient elastomeric material which is designed to close about small objects, such as a guide wire, as well as about larger objects, such a working catheter to prevent air or blood leakage. The gasket includes an angled slit in a central member which is positioned between proximal and distal cylindrical members each having a central bore in alignment with the angled slit. While satisfactory for certain applications, this gasket must be separately manufactured and located within the introducer, which adds cost and complexity to the overall device. Function, moreover, is friction dependent.
In U.S. Pat. No. 4,684,364, there is disclosed a flow control device having a tubular structure with input means and output means each provided with an open bore, channel means connecting the input and output bores and operating between open and closed positions, and clip means for retaining a portion of the channel means in a prestressed condition to obturate the channels means so as to maintain it in a closed position. The channel means is forcible to an open position in response to a positive pressure in either one of the bores to facilitate flow through the channel means from the bore containing the positive pressure to the other bore. Also, the flow control device is capable of passing fluid in either direction depending upon which bore contains the positive pressure, with the clip means returning the channel means to the closed position when the positive fluid pressure is removed.
U.S. Pat. No. 4,722,725 discloses a catheter means comprising an elongated body portion for insertion into a patient, at least one integral hub portion adjacent to the body portion, and at least one fluid flow control means located in either the body or hub portion adjacent to the body portion, and at least one fluid flow control means located in either the body or hub portion or adjacent to the hub portion. The fluid flow control means may be integral with or releasably secured to its respective hub portion. Also, obturating means for rendering incompetent the fluid flow control means can be used.
In U.S. Pat. No. 4,784,644, there is disclosed a novel valve comprising a disc member for use in a fluid flow control means. This fluid flow control means can be incorporated into a catheter and used for delivering or removing fluids to or from a patient.
U.S. Pat. No. 4,883,461 discloses a fluid flow control means incorporated into a catheter, with the control means comprising a disc valve.
The fluid flow control means described in the four preceding patents may not completely prevent the reflux of fluid from a vessel. In the neutral position, the disk valve is competent and no reflux of fluid can occur. However, when the physician inserts a medical apparatus, hereinafter referred to as a device, into an introducer which includes the valve, the valve will become partially incompetent. For example, when the physician inserts a catheter into the introducer, the disk is pushed aside, creating small areas on either side of the catheter which can permit the reflux of fluid.
Accordingly, the present invention is directed to a new and effective method for preventing the reflux of fluids associated with the introduction of a catheter system into the vascular tree, said system comprising a transcutaneous introducer catheter. In addition, the present invention provides means for increasing the tactile sensation and manipulating ability of a device operated in conjunction with a transcutaneous introducer catheter. In order to prevent the reflux of fluid through or around these devices, the present invention incorporates the use of an integral skirt or molded plug which forms around the hemostatic seal around the device when it is inserted in the catheter valve.